\subsection{Units of measure}
\index{units of measure}
Quoted strings can be used to express units of measurement in a calculation.
For example, the space shuttle accelerates from zero to
17{,}000 miles per hour in 8 minutes.
The average acceleration of the space shuttle is

\medskip
\verb$v=17000*"mile"/"hr"$

\verb$t=8*"min"/(60*"min"/"hr")$

\verb$v/t$
$$127500\,\hbox{mile}\over(\hbox{hr})^2$$

